Production of mutant streptokinase recombinant protein

Streptokinase (SK) is most widely used for treatment of myocardial infarction, however, it is the most expensive thrombolytic agent. A major drawback to SK use is the widespread presence of anti–streptokinase antibodies (Abs). These Abs cause allergic reactions and neutralize streptokinase therapeutic effects. To produce an engineered variant of streptokinase being functional and less antigenic than the native molecule, we cloned and expressed streptokinase mutant gene lacking the C – terminal 42 amino acids. Recombinant protein was confirmed by western blot analysis with anti T7 monoclonal antibodies. pGEMEX-1 expression vector contains T7 gene 10 protein as fusion protein immediately down stream of T7 promoter and before multiple cloning site, streptokinase mutant gene was cloned after fusion protein. We cloned and expressed mutant streptokinase gene, lacking the C-terminal 42 amino acids. If mut-C42 activity was less affected by neutralizing antibodies compared with native streptokinase, this engineered variant could be a preferred alternative to native streptokinase for thrombolytic therapy.